He was arrested on suspicion of murder by the Independent Police Complaints Commission after fatally shooting 28-year-old Jermaine Baker in Wood Green, North London in December 2015.

Baker, of Tottenham, was sitting in the front passenger seat of a car with two other men planning to hijack a prison van taking a Turkish gang leader due to be sentenced at nearby Wood Green crown court when he was shot with a single bullet.

He was unarmed but an imitation Uzi machine gun was found in the back passenger footwell behind the driver’s seat.

Fellow gun cops threatened to tear up their ‘blue ticket’ gun licences if the decision went against the police officer

They said in a statement: “The prosecution could not prove to the required standard that W80 was being untruthful about his belief that Mr Baker was armed and reaching for a weapon to fire on the officers.”

However, the decision is certain to lead to community tensions in an area where the nationwide riots of August 2011 were sparked off.

The IPCC said it was sending a file to the Met with a recommendation on whether W80 had committed any misconduct disciplinary offences and was waiting to hear from the London force.